And now, a game a lot more obscure than Dwarf Fortress. Oh, and, click the images to enlarge them! (Right-click + View Image works just as well, too)

Aurora

Aurora is a free indie game developed by Steve Walmsley, a hobbyist programmer with a damn intuitive and involved game. Steve is a professional poker player, and he works on Aurora alone, part-time. Aurora is one of the most impressive games I've come across throughout my years on the internet. It is also truely an obscure game. Aurora boasts some of the most detailed gameplay you'll ever come across, in fact, so detailed it makes playing the game a borderline mind-boggling experience.

I use the the term mind-boggling quite literally. It will take you days, if not weeks, at the least to learn the ropes of the game entirely. The game's combat is so detailed, so involved, so complicated in a "oh-my-god-what-the-hell-do-these-things-do?!" way. Not to mention, the game does not at all tell a player what to do once they start playing. You won't have the slightest clue what you're supposed to be doing once you begin the game, and believe me, sitting around and trying to do things on your own will do more harm than good. Not to mention the game can progress extremely slowly sometimes.

But just what is Aurora? By now if you're not the slightest bit curious... you are a horrible, horrible person!

Exploring an alien homeworld...

Aurora is a 4x (eXplore, eXpand, eXploit, and eXterminate) game about managing the human race (or a custom-made race) in the 2025-ish era. In the vanilla scenario, you command the combined nations of the world under the "Terran Federation". Aurora is about managing humanity during the first years of their interstellar travel, to the point where it's a very trivial thing. In Aurora, you expand your empire to other planets and gather precious "Trans-Newtonian" materials that are vital in the construction of advanced machinery and planetary establishments.

The game will have you micro-managing your empire's economy, overseeing your civilian sectors, colonizing and terraforming new worlds, and fighting for your empire's survival against the many threats in space. You'll be doing all of this in a much, much more in-depth and involved perspective than your traditional strategy game. Terraforming worlds that are far from meeting the requirements for your humans will take valuable resources and economic power, along with several years or decades to complete. It may prove more profitable in the long-run to establish a genetically-modified subrace of humans to inhabit a planet normally uninhabitable by humans.

Before all of this happens, however, you have to create your ships from the ground-up. The game won't hold your hand with this, and will give you the naked interface to create your ships and tell you to have fun! This really is the beautiful part of the game, because you can create almost anything. Not to mention you can fine-tune virtually every aspect of your ship. In order to build your ship, you have to design your ship's components. In order to design components, you have to commit a significant amount of scientific manpower to the task. Once you have your components, you place them in your ship's design and you can begin manufacturing that ship as much as you want!

The ships in Aurora aren't what you think. They're not the Enterprise from Star Trek that can serve many functions with only a handful of crew members. In Aurora your ships will be better off serving different functions in a theoretical squad; a ship that scans targets and provides the data required for other ships to lock on and fire, a ship that carries fighters, a ship that fires only kinetic ordinance, and a ship that fires only kinetic ordinance to fend off against incoming enemy contacts (Point Defense).

I could go on forever about this game and its AI, randomly-generated star systems, randomly generated AI-controlled alien empires, combat, etc. but that would spoil everything! Why don't you just play this game yourself?

I use the the term mind-boggling quite literally. It will take you days, if not weeks, at the least to learn the ropes of the game entirely. The game's combat is so detailed, so involved, so complicated in a "oh-my-god-what-the-hell-do-these-things-do?!" way. Not to mention, the game does not at all tell a player what to do once they start playing. You won't have the slightest clue what you're supposed to be doing once you begin the game, and believe me, sitting around and trying to do things on your own will do more harm than good. Not to mention the game can progress extremely slowly sometimes.

This sounds like the worst game ever. You said some aspects of the game are fun, but this paragraph turned the statement "it's fun" into "it's fun... but way too complicated."